Injection molding machine should consider several points: 1 ???, components requirements: security-related functions of the control circuit in the design, selection and assembly process must use mature technology components that should be in a similar ????? ? have been used widely and successfully in the field of use, or based on reliable safety standards manufactured components, and the use of proven technology. ?????? Safety control circuit to be able to withstand the expected operating strength to withstand the impact of the working medium during operation of the impact and associated external environment. The use of technology is mature ELEMENTS ?????? pieces that have similar applications in the field extensively and successfully used, or according to a reliable security standards for manufacturing of components, and the use of sophisticated technology ???? ?? surgery. In the design of the circuit, the work should be extremely safe and reliable components, you can not consider the possibility of failure of this component itself. Meanwhile, in order to avoid short-circuiting ?????? reduce the incidence of failure, determine the type of fault, to accurately detect failures and avoid secondary faults, can be used as such ??????: isolation circuit, fully carrying capacity, when the case of failure timely open power, a good grounding and other measures. ??? 2, machine safety stop request: security equipment, its core is to make the equipment dangerous actions stopped, how ?????? equipment to be stopped from running is very important. Depending on the security device used, can have different safety stop function. In normal operation, stop using ?????? feature, you must be able to avoid the equipment, products and processes to be destroyed, but to be able to prevent the restart of machinery and equipment, which is safe stop ?????? functional requirements.